The pair have shared a fractious relationship for years, dating back to Benitez's spell in charge of Liverpool and highlighted by the Spaniard's famous rant four years ago in which he suggested Ferguson was never punished for verbally abusing referees and their assistants.

The Scot has been contacted by the Football Association to explain comments and has until 6pm on Thursday to respond.

"It's a question for the FA what they do about it," Benitez added. "What I said at that time was what I thought, and what I'm seeing now is similar.

"It depends on the FA. I don't know what they will do - it depends on them. At this moment in time I have enough things to do here, so I want to concentrate on my job."

Benitez, meanwhile, has warned Swansea's Michael Laudrup of the challenges of management at the highest level ahead of Wednesday night's Capital One Cup semi-final second leg.

Laudrup has impressed since moving to the Liberty Stadium as successor to Liverpool's Brendan Rodgers and the style Swansea employ has attracted admirers.

Further success at Swansea could see the Dane move to a club challenging at the top end of the Barclays Premier League, possibly even Chelsea, where tactics are one of numerous concerns.

Benitez said: "The style of football the team had under (Paulo) Sousa, Roberto Martinez and Brendan Rodgers was good for him because it's the way that he likes to play.

"But when you're managing in the middle of the table it's easy to bring in young players, it's easy to play a certain style. It's when you're at the top or the bottom when it's harder to impose your ideas.

"Football is quite complicated now. You have to manage a lot of things. That's something you have to analyse carefully."